Adhesives have been used in adhesion of any kinds of materials, e.g. plastics, glass, metals, wood, ceramics, rubber, paper, cloths, leather, and the like. Recently, in terms of recycling, it has been required to separate adherends once stuck with adhesives and reuse them. However, depending on the types of adhesives and the properties and shapes of the adherends, it has not been easy to separate adherends. Especially, in the case the adhesive strength is firm or in the case a fragile adherend has to be separated without being damaged, very complicated operation is required.
For example, a laminate glass, which is obtained by sandwiching an adhesive or an intermediate film for laminate glass made of a thermoplastic resin sheet such as a polyvinyl butyral resin sheet between glass plates and bonding them together, has been used widely as glass for vehicles such as automobiles and aircrafts or for window glass of constructions for preventing scattering of glass, injuries and damages on human bodies and appliances by glass in the case of collision of an object to the glass or for preventing crimes. With respect to such a laminate glass, it has been required to reuse the glass and the intermediate film for laminate glass by disassembling the used laminate glass in terms of recycling. Further, for example, extremely strict quality standards have been imposed on adherends to be used for automobiles and air crafts, those in which foams are entrained at the time of lamination of the glass are regarded as inferior products. Especially in the case of a front glass having a large surface area, such entrainment of foams tends to occur easily and taking the use amount of the laminate glass all over the world into consideration, it can be assumed that an immense amount of inferior products are produced. To recovery the glass and intermediate films for glass from such inferior products is very important and challenging issue in terms of saving cost and advantageous utilization of resources.
For that matter, Japanese Kokai Publication 2001-104928 discloses a method of reusing glass fragments peeled off the adhesive by crushing a laminate glass into small pieces. However, in the case of using this method, a large quantity of adhesive bearing glass fragments and an intermediate film for laminate glass are left, and the object matter to reproduce them is not solved. The adhesive bearing glass fragments and the intermediate film for laminate glass cannot be incinerated in a general incinerator and they cannot be treated but incinerated by employing a special furnace.
Japanese Kokai Publication Hei-6-247751 discloses a method of respectively separating and recovering an inner plate and an outer plate by heating a laminate glass to a temperature at which the intermediate film for laminate glass is softened. However, even by this method, actually it is not easy to carry out the separation in the case of glass with a large size such as automotive front glass and there is a problem left that the adhesive remains in the surface of the glass.
Japanese Patent No. 3137504 describes a method of separating an intermediate film for a laminate glass from the laminate glass by putting the laminate glass crushed in small pieces in a water tank, while swelling the intermediate film, and simultaneously applying shearing force to the intermediate film by stirring the small pieces with specified speed difference. However, although it is possible for this method to reuse the glass portions, it is impossible for the intermediate film portions to be completely separated from the crushed glass fragments and therefore, it is a problem of the quality to reuse them as an intermediate film for laminate glass as they are and the intermediate film portions have to be disposed as industrial wastes.
Japanese Kokai Publication Hei-6-219793 discloses a method involving cooling a laminate glass to −10° C. or lower for decreasing the adhesive strength between the interlayer film for laminate glass and glass and then applying an impact the adherend for crushing the glass and at the same time separating and recovering the interlayer film for laminate glass. However, this method is incomplete in the separation of the glass and interlayer film for laminate glass and there still remains a problem of the quality of the glass and the interlayer film for laminate glass for reuse as they are and they have to be disposed as industrial wastes.
Japanese Kokai Publication 2003-160668 and 2003-285042 disclose methods of removing interlayer films for a laminate glass from glass by immersing laminate glass crushed into small pieces in organic solvents and thereby dissolving the laminate glass.
However, by these methods, it costs high to recover the components of the interlayer film for laminate glass from the organic solvents and to reuse them and further there is another problem that the methods have risks of heavy loads on the environments since a large quantity of organic solvents are used.
Further, electronic materials comprising electronic part laminates composed by layering electronic parts at a high integration degree have been used widely. Adhesives have been employed for connection of these electronic parts. However, even if it is tried to recover and recycle electronic parts from electronic part laminates or it is tried to re-fabricate them in the case defective failure occurs during fabrication process, it has been very difficult to remove the electronic parts stuck to adhesives. For example, Patent Document No. 3 discloses a semiconductor device comprising a semiconductor element stuck to a substrate by previously forming a hole smaller than the outer shape of the semiconductor element in a semiconductor element mounting part of the semiconductor element mounting substrate, providing an adhesive on the substrate having the semiconductor element mounting part, and disposing the semiconductor element on the adhesive. It aims to make adhesion strength weak and make recovery easy by suppressing the adhesion portions of electronic parts to the minimum. However, such a method has a restriction in the position to form the hole therein and results in cost up and further there is a serious disadvantage that the strength of the electronic part laminate to be obtained becomes weak. As a result, electronic part laminates could not have been treated but discarded entirely so far.
Further, also in the case of recovering and recycling paper from books which are produce by binding with adhesives and collected as wastepaper, separation of paper and adhesives becomes a challenging matter. Japanese Kokai Publication Hei-6-080945 discloses a method of removing an adhesive from books by using an adhesive easy to remove by a filter since it has a high strength and cannot be cut by a pulper. However, since this method is limited in the types of adhesives usable, the method is not suitable for recycling of a wide range of books.
Recovery and re-use of steel cans is also very important, however conventionally there is no means but incineration of coating resins as disclosed in Japanese Kokai Publication Hei-9-227957 and even such a method has problems that it is difficult to completely burn out the coating resin and that residues of carbonized coating resins are left.
Japanese Kokai Publication 2002-343760 has a description of a method of physically and chemically removing organic polymer substances adhering or deposited on objects to be washed by spraying water or a polar solvent in supercritical or subcritical state under high pressure atmosphere. However, in this method, water or a polar solvent in supercritical or subcritical state cannot be sprayed directly to organic polymer substances formed thin between two pieces of an object to be washes or to organic polymer substances adhering to an object to be washed having complicated shape and therefore, there is a problem that the application of the method is considerably limited in a very narrow range.